DESCRIPTION: Biomaterials surfaces play an important role in the overall implant success. The objectives of this study are: to compare the performance of surface treated Ti implants to non-surface treated Ti implants in relation to bone implant interface and bone strength; and to investigate the long-term impact on bone remodeling as a result of loading the plasma sprayed titanium implants, plasma sprayed HA implants and non-surface treated TI implants. Aim will evaluate in vitro properties of plasma sprayed HA surfaces and compare their in vitro properties in cell culture medium containing serum with that of TI coated implants treated similarly. Aim 2 will compare the in vivo performance in dogs of plasma sprayed HA and TI implants with non- treated TI implants in terms of bone implant interface, interfacial strength, and coating resorption. Hypotheses to be tested are: 1) that the surface properties of HA coatings will be altered following in vitro incubation and thus will affect their in vivo stability; 2) prior to loading, the presence of plasma sprayed HA and TI coatings will result in an increase in bone implant bonding strength an greater bone apposition when compared to non-surface treated TI surfaces; and 3) after one year loading, differences in reverse torque and bone apposition will be observed among plasma sprayed HA and TI implants, and untreated TI implants. At present, implants are often placed clinically prior to the conduct of basic experimental studies elucidating the remodeling mechanisms that may enhance clinical serviceability. Data generated by this pilot study could provide needed information on HA surface properties, provide preliminary information on relationships among the different surfaced implants, and provide a basis for future long-term in vivo clinical studies, while suggesting an optimum surface treatment required for maximum implant stability. These result could reduce implant failures which are costly in terms of trauma, time, and money.